package thread;

class Print {
    private  int flag = 1;//信号量，当为1时打印数字，2 打印字母
    private int count = 1;

    public synchronized void printNum() {
        if (flag != 1) {
            try{
                wait();
            }catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        System.out.print(2* count -1);
        System.out.print(2* count);
        flag = 2;
        notify();
    }

    public synchronized void printChar() {
        if (flag != 2) {
            try{
                wait();
            }catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        System.out.print((char) (count -1 + 'A'));
        count ++;
        flag = 1;
        notify();
    }
}

public class WaitNotify {
    public static void main(String[] args) {
        Print print = new Print();

        new Thread(() -> {
            for (int i = 0; i < 26; i++) {
                print.printNum();
            }
        }).start();

        new Thread(() -> {
            for (int i = 0; i < 26; i++) {
                print.printChar();
            }
        }).start();
    }
}
